In the field of tools, and more specifically relating to screwdrivers, the use of magnetised materials at the tip is known to facilitate the gripping of the screw head, so that the operation of turning it is facilitated by the magnetised material used to keep the screw held in place. These types of screwdrivers generally feature the drawback that they do not have a sufficient force of attraction to guarantee a positional stability of the screw and prevent the need for one to use their other hand to hold the screw in place.
Some solutions intended to resolve this drawback are known, such as the case of patent of application DE202004016173, which discloses a magnetic screw holder which is built into the rod and has a magnet at the tip in the shape of a cap which would facilitate the attraction of the screw, overcoming the abovementioned drawback. However, this cannot be separated; the body is rigid and requires the use of coupling means which establishes connection thereof with the screwdriver. All of this increases the cost of the array.
Another solution included in the patent of application WO2008043514 claims a hard plastic tubular element, which can only be adapted to cylindrical rod screwdrivers, and is equipped with fixing elements which, by means of screwing, establish its link to the screwdriver rod in a specific position to adapt the position of the magnet to the depth of the hollow of the screw head. This mode of fastening is inconvenient when the operating conditions require movement back to its original position.
In the patent of application DE102009003404, a non-magnetic screw-finder that has a tubular configuration for the coupling thereof by sliding in the screwdriver rod is disclosed, made of elastomeric plastic and having stubs or claws made of another, harder plastic material, which extend from one of its ends and which are devised to hold the screw head. These stubs cause the system to be complex, bulky, difficult to handle, and since there is partial contact between the screw head and the stubs, the screw can wobble easily.
Other tubular gripping elements have a rigid, cylindrical body configuration that extends in generally metallic, flexible stubs, near their ends, to couple to the rod, resulting in an unsuitable solution due to the positional instability offered, and have low or null electrical insulation.
Other devices are arranged along the entire rod so that they can be actuated from the screwdriver handle itself. This requires plenty of dexterity from the user and their connection to the screwdriver makes them bulkier and more costly.
All of these examples have a single operational sense, in that they fix to the rod at one end and fix to the screw at the other.
In the case of the technical field of writing instruments, some tubular gripping elements are known which are coupled by sliding onto the writing instrument, particularly onto pencils, but normally they are very thick and soft, of non-uniform thickness and variable geometry. They are generally used as postural correctors for children with writing problems, with specific supports which force the child to adopt a singular position with their fingers, regardless of the size thereof, in many cases limiting their use depending on whether the user is right-handed or left-handed, being truly impractical and non-ergonomic for most users. As an example, one can look at the patent of application U.S. Pat. No. 5,143,463.
In the case of ballpoint pens, the use of gripping elements is also known which facilitate the handling and operation thereof during writing. These elements are immobilised and built into the structure of the ballpoint pen itself.